1. No category

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Redox Reactions
1) Which element undergoes disproportionation in water?
2) F2
3) K
4) Carbon
Ans: 1, Cl2+H2O→HCl+HClO
1) +3
(PMT2011)
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2) Oxidation state of phosphorus in metaphosphoric acid is
co
m
1) Cl2
(DPMT2011)
2) +5
3)-3
Ans: 2, HPO3
4) +2
3) In the redox reaction xKMnO4+y NH3→KNO3+MnO2+KOH+H2O
(DPMT2009)
1) x = 4, y=6
2) x=3,y=8
3) x=8, y=6
4) x=8,
y=3
ks
hi
Ans: 4 [8KMnO4+3NH3→8KNO3+3MnO2+5KOH+2H2O]
4) Oxidation number of P in PO4-3, S in SO4-2 and that of Cr in Cr2O7-2 are
.s
a
respectively
2) +5, +6 &+6
3) +3, +6 &+5
4) +5, +3 &+6
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1)-3, +6 &+6
(PMT2009)
w
w
Ans: 2
5) Hydrogen is prepared from water by adding
1) Ca, which acts as reducing agent
3) Ag, which acts as reducing agent
(DUMET2011)
2) Al, which acts as Oxidising agent
4) Au, which acts as Oxidising agent
Ans: 1, Ca+2H2O→Ca (OH) 2+H2
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6) Number of moles of MnO4- required to oxidize one mole of Ferrous Oxalate in
acid medium will be
1) 0.5 moles
(PMT2008)
2) 0.2 moles
3) 0.6 moles
4) 0.4 moles
3 moles MnO4- oxidize 5 moles of Ferrous Oxalate.
co
m
Ans: 3, 3 MnO4- +5Fe+2 +5C2O4-2+24 H+→3Mn+2+5Fe+3+10CO2+ 12 H2O
Moles of MnO4- that oxidize 1 moles of Ferrous Oxalate=3/5 =0.6
1) +6
2) +4
Ans: 3
(CPMT2008)
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7) Oxidation state of Fe in K4 [Fe (CN)6]
3) +2
4) +5
8) Oxidation state of P in H4P2O5, H4P2O6 and H4P2O7 are respectively
(AIPMT2010)
1)+3,+5,+4
3)+5,+4, +3
4)+3,+4 ,+5
hi
Ans: 4
2)+5,+3,+4
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9) The oxidation state of S in H2S2O8 is
2) +4
3) +6
4) +7
.s
a
1) +2
(PMT2007)
Ans: 3, it has 6 normal and 2 peroxy oxygen atoms
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10) Nitrogen forms a variety of compounds in all oxidation states ranging from
1)-3 to +5
(PMT2006)
2)-3 to +3
3) -3 to +4
4) -3 to +6
Ans: 1, Lowest state= group number-8= 5-8= -3, Maximum state = +group number=
+5
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